Acoustic Challenges Research Articles

Acoustic noise in a small-format 3.0-T neonatal MRI system.

Today, magnetic resonance imaging (MRI) is rarely used in managing the care of premature neonates. This is in large part due to the medical and logistical challenges associated with moving neonates from the neonatal intensive care unit (NICU) to the radiology department. Furthermore, acoustic noise associated with MR scanning poses safety concerns for both practitioners and neonatal patients. A small-format 3.0-T neonatal scanner was recently developed and placed within the NICU to address these logistical and acoustic challenges. To compare acoustic noise measurements of a small-format 3.0-T neonatal MRI scanner with conventional adult-sized 1.5-T and 3.0-T MRI scanners using identical neonatal head imaging protocols. Sound pressure level (SPL) measurements of a standard imaging protocol were made in a small-format neonatal 3.0-T MRI scanner as well as in adult-sized 1.5-T and 3.0-T scanners. SPL measurements were made with a Brüel & Kjær sound level meter model 2250. The statistical significance of the differences in SPL between scanners was determined using one-way ANOVA. Average sound pressure level values were measured in unweighted decibels (dB) and A-weighted decibels (dBA) for all imaging sequences in the protocol. The average A-weighted SPLs for the NICU from 1.5-T and 3.0-T MRI scanners were 81.02 ± 0.28 dBA, 87.00 ± 0.85 dBA, and 94.91 ± 0.65 dBA, respectively. SPLs at the isocenter of the NICU MRI scanner were 5.98 dBA quieter than in the 1.5-T scanner (P=0.007), and 13.89 dBA quieter than in the 3.0-T scanner (P<0.001). For staff standing next to the scanner, the NICU scanner was 20.24 dBA quieter than the 1.5-T scanner (P<0.001) and 19.28 dBA quieter than the 3.0-T scanner (P<0.001). The NICU 3.0-T MRI system is significantly quieter than conventional adult-sized MRI systems, improving safety for neonatal patients. Significant reductions in SPL were also noted inside the screen room where clinicians may be present during scanning.

Insights from the "Acoustics Workshop in Educational Buildings" by Turkish Acoustical Society

This paper focuses on "Acoustics Workshop in Educational Buildings" organized by the Turkish Acoustical Society as part of International Noise Awareness Day 2023 Activities. The workshop brought together 34 participants, including designers, acoustic experts, teachers, and health and occupational safety professionals. Through interdisciplinary discussions, participants identified and prioritized acoustic problems, expectations and requirements for educational buildings, focusing on improving the quality of education. The workshop unfolded in two stages: firstly, participants were grouped by profession to identify primary acoustic challenges. Subsequently, multi-disciplinary teams collaboratively developed mitigation strategies to address these challenges. The results revealed profession-specific insights into main acoustic issues and proposed actionable solutions. This paper specifically provides insights into the use of qualitative content analysis to have a deeper understanding of different professions, people's experiences, behavior and priorities in relation to acoustics in school.

The Costs (and Benefits?) of Effortful Listening for Older Adults: Insights from Simultaneous Electrophysiology, Pupillometry, and Memory.

Although the impact of acoustic challenge on speech processing and memory increases as a person ages, older adults may engage in strategies that help them compensate for these demands. In the current preregistered study, older adults (n = 48) listened to sentences-presented in quiet or in noise-that were high constraint with either expected or unexpected endings or were low constraint with unexpected endings. Pupillometry and EEG were simultaneously recorded, and subsequent sentence recognition and word recall were measured. Like young adults in prior work, we found that noise led to increases in pupil size, delayed and reduced ERP responses, and decreased recall for unexpected words. However, in contrast to prior work in young adults where a larger pupillary response predicted a recovery of the N400 at the cost of poorer memory performance in noise, older adults did not show an associated recovery of the N400 despite decreased memory performance. Instead, we found that in quiet, increases in pupil size were associated with delays in N400 onset latencies and increased recognition memory performance. In conclusion, we found that transient variation in pupil-linked arousal predicted trade-offs between real-time lexical processing and memory that emerged at lower levels of task demand in aging. Moreover, with increased acoustic challenge, older adults still exhibited costs associated with transient increases in arousal without the corresponding benefits.

Task-Specific Rapid Auditory Perceptual Learning in Adult Cochlear Implant Recipients: What Could It Mean for Speech Recognition.

Speech recognition in cochlear implant (CI) recipients is quite variable, particularly in challenging listening conditions. Demographic, audiological, and cognitive factors explain some, but not all, of this variance. The literature suggests that rapid auditory perceptual learning explains unique variance in speech recognition in listeners with normal hearing and those with hearing loss. The present study focuses on the early adaptation phase of task-specific rapid auditory perceptual learning. It investigates whether adult CI recipients exhibit this learning and, if so, whether it accounts for portions of the variance in their recognition of fast speech and speech in noise. Thirty-six adult CI recipients (ages = 35 to 77, M = 55) completed a battery of general speech recognition tests (sentences in speech-shaped noise, four-talker babble noise, and natural-fast speech), cognitive measures (vocabulary, working memory, attention, and verbal processing speed), and a rapid auditory perceptual learning task with time-compressed speech. Accuracy in the general speech recognition tasks was modeled with a series of generalized mixed models that accounted for demographic, audiological, and cognitive factors before accounting for the contribution of task-specific rapid auditory perceptual learning of time-compressed speech. Most CI recipients exhibited early task-specific rapid auditory perceptual learning of time-compressed speech within the course of the first 20 sentences. This early task-specific rapid auditory perceptual learning had unique contribution to the recognition of natural-fast speech in quiet and speech in noise, although the contribution to natural-fast speech may reflect the rapid learning that occurred in this task. When accounting for demographic and cognitive characteristics, an increase of 1 SD in the early task-specific rapid auditory perceptual learning rate was associated with ~52% increase in the odds of correctly recognizing natural-fast speech in quiet, and ~19% to 28% in the odds of correctly recognizing the different types of speech in noise. Age, vocabulary, attention, and verbal processing speed also had unique contributions to general speech recognition. However, their contribution varied between the different general speech recognition tests. Consistent with previous findings in other populations, in CI recipients, early task-specific rapid auditory perceptual, learning also accounts for some of the individual differences in the recognition of speech in noise and natural-fast speech in quiet. Thus, across populations, the early rapid adaptation phase of task-specific rapid auditory perceptual learning might serve as a skill that supports speech recognition in various adverse conditions. In CI users, the ability to rapidly adapt to ongoing acoustical challenges may be one of the factors associated with good CI outcomes. Overall, CI recipients with higher cognitive resources and faster rapid learning rates had better speech recognition.

Case study: Computer modeling the noise produced by a future food court radiated to nearby existing offices

Lately, there’s an increase in the co-existence of spaces of different usage with acoustical challenge. Throughout 2016 to 2018, the 2nd floor of the Complexe Les Ailes, in Montreal, underwent a fit-out to become a food court. At its center, there is an elliptical atrium where all levels are can be viewed. There are existing offices above the food court separated by a glass pane. The purpose of this study was to evaluate the noise generated by human activities in the future food court to the adjacent offices and recommend noise control elements if needed. Multiple sound samples were taken at existing food courts to quantify the sound level. Simulations were done with ODEON, a room acoustic software, to evaluate the sound level produced by different activities. On-site measurements were conducted to calibrate the existing conditions with the 3D ODEON model. Finally, noise reduction tests were undertaken to determine the sound levels that would be radiated in the offices by the activities in the food court. To reduce noise disturbance in the offices, acoustical treatment under the ceiling of the food court was recommended and the 3rd and 4th floor glass panes composition would have to be improved.

Advancements in nanotechnology for acoustic management in pickleball

This research investigates the use of advanced nano-fiber technology for sound and noise management in pickleball courts. The technology, known for its flexibility and adaptability, addresses the unique acoustic challenges of pickleball, a sport with a distinctive noise profile characterized by impulsive and unpredictable sounds. These nano-fibers are particularly effective in absorbing mid to high-frequency noises (800–5000 Hz) common in pickleball. Incorporating these nano-fibers into acoustic foams and textiles significantly enhances sound absorption, allowing for thinner materials while doubling performance compared to conventional materials. These fibers, about 1/500th the diameter of human hair, have a high surface area to volume ratio, aiding in sound scattering and increased friction with air molecules. This structure enables the efficient transformation of sound energy into heat, which is then effectively dissipated. Aligned with the Acoustical Society of America's standards, this abstract emphasizes a scientific breakthrough in sports acoustics, contributing to the reduction in urban noise pollution. The study underscores the impact of cutting-edge material technology in improving environmental acoustics and community well-being.

Use of a micro acoustic chamber for rapid iterative design, teaching, and demonstration in the development of innovative lower-carbon mass timber assemblies

Mass timber construction offers a range of benefits to the design industry, including the potential for sustainability and reduced building embodied carbon, biophilia, speed of assembly, and prefabrication. However, these benefits can create acoustical challenges for sound isolation between spaces. Thus, the University of Oregon’s Institute for Health in the Built Environment, in collaboration with the TallWood Design Institute, has developed a micro acoustic chamber as a conceptual testbed, educational resource, and demonstration tool for design professionals and students, to develop new and innovative mass timber acoustic assemblies, understand acoustic implications of material choices in composite form, and comparatively analyze the performance of acoustic detailing decisions more rapidly at a small scale. The chamber hosts specimens that are 813 mm × 813 mm and up to 300 mm thick, far smaller than a typical laboratory acoustic floor/ceiling assembly test chamber, creating known limitations; however, test samples can be cost and material efficient, allowing relative performance differences between assemblies to be evaluated quickly and easily for initial design feedback. This presentation will share how the use of a micro acoustic chamber has been integrated into design education, student, and industry pilot research to accelerate the development of mass timber acoustic solutions.

Modular design for optimized acoustic properties of multilayer system

It has been demonstrated that multilayer systems have the potential for excellent sound absorption, effectively attenuating sound across a wide range of frequencies and offering a versatile solution for addressing acoustic challenges in various environments. A key consideration is the design of a multi-layer structure and the parameters of each layer to achieve optimal sound absorption performance. Modular design is a crucial aspect of this work, involving the creation of smaller, units that can be customized and combined to achieve specific sound absorption properties. This study applies numerical optimization, inversion, and matrix methods to multilayer sound absorber systems, aiming to provide customized parameters for the modular design of fibrous materials with exceptional sound absorption properties. The effectiveness of the modular design will be validated and improved through impedance tube measurements of the manufactured multilayer systems, ensuring that the resulting sound absorbers meet the desired acoustic performance across diverse real-world scenarios.

Sound transmission loss through steel-framed building partitions

Load-bearing steel-stud walls pose a unique acoustical challenge because both the spacing and the mil thickness of the studs can significantly affect the acoustical performance of these walls. A single wall type in a load-bearing steel building may actually include many acoustically distinct walls as the stud spacing and mil thickness change from floor to floor in the building due to the different loads. This can be especially challenging on delegated design projects where the final selection of the steel studs is left to the framing contractor and may not be included in the project documents supplied to the acoustical consultant, if there even is one on the project. In prior ASA presentations, Ben Shafer has clearly documented the effects of steel stud spacing and mil thickness on acoustical performance. This presentation adds to Ben’s prior work by investigating the effects of resilient sound isolation clips on wall performance. Clips are a unique application because the spacing of both the clips, and the hat channels does not change with changing stud spacing and because the low stiffness of the rubber isolators should reduce the effect of stud stiffness. This presentation will present the results of recent lab tests of walls with resilient sound isolation clips and compare the results to the data previously presented by Mr. Shafer.

Effects of linguistic context and noise type on speech comprehension.

Understanding speech in background noise is an effortful endeavor. When acoustic challenges arise, linguistic context may help us fill in perceptual gaps. However, more knowledge is needed regarding how different types of background noise affect our ability to construct meaning from perceptually complex speech input. Additionally, there is limited evidence regarding whether perceptual complexity (e.g., informational masking) and linguistic complexity (e.g., occurrence of contextually incongruous words) interact during processing of speech material that is longer and more complex than a single sentence. Our first research objective was to determine whether comprehension of spoken sentence pairs is impacted by the informational masking from a speech masker. Our second objective was to identify whether there is an interaction between perceptual and linguistic complexity during speech processing. We used multiple measures including comprehension accuracy, reaction time, and processing effort (as indicated by task-evoked pupil response), making comparisons across three different levels of linguistic complexity in two different noise conditions. Context conditions varied by final word, with each sentence pair ending with an expected exemplar (EE), within-category violation (WV), or between-category violation (BV). Forty young adults with typical hearing performed a speech comprehension in noise task over three visits. Each participant heard sentence pairs presented in either multi-talker babble or spectrally shaped steady-state noise (SSN), with the same noise condition across all three visits. We observed an effect of context but not noise on accuracy. Further, we observed an interaction of noise and context in peak pupil dilation data. Specifically, the context effect was modulated by noise type: context facilitated processing only in the more perceptually complex babble noise condition. These findings suggest that when perceptual complexity arises, listeners make use of the linguistic context to facilitate comprehension of speech obscured by background noise. Our results extend existing accounts of speech processing in noise by demonstrating how perceptual and linguistic complexity affect our ability to engage in higher-level processes, such as construction of meaning from speech segments that are longer than a single sentence.

Quantifying acoustic performance and embodied carbon of acoustic solutions for mass timber buildings: Comparing common approaches around the globe

As mass timber continues to increase in popularity as a building method to shifting away from high embodied carbon concrete structures to utilize wood as a renewable and lower embodied material. As whole building life cycle assessments (LCA) become more essential in meeting environmental emissions targets and qualifying for sustainability linked financing, quantifying the embodied carbon of both the structure and all other elements is necessary. The acoustic challenges of mass timber have been well documented and studied in previous works with a range of solutions now commonly utilized. Like most elements of construction, regionality results in different techniques being more popular and practical in different parts of the world. This work will compare the airborne and structure borne sound transmission and associated embodied carbon of four common acoustic designs for mass timber construction: floating concrete toppings, isolated board and batten floor systems, isolated dry floor linings, and raised access floors.

Laboratory measurements of lightweight floating floor systems on cross-laminated timber (CLT) slabs

Mass timber family of products (including cross-laminated timber - CLT) offer an alternative to fossil fuel-intensive materials for many applications and an opportunity to reduce the carbon footprint of the built environment. However, the use of mass timber in multi-family and commercial buildings presents unique acoustic challenges. Additionally, one of the most desired aspects of mass timber construction is the ability to leave a building's structure exposed as finish, which creates the need for asymmetric assemblies. This means that when speaking about floor/ceiling applications, preferentially any acoustical component should be installed on top of the assembly. To measure airborne sound reduction and impact noise isolation of lightweight floating floor systems and confirm CLT assemblies can provide satisfactory sound insulation, CDM Stravitec launched a testing campaign (done on Belgian Building Research Institute, institution recognized by application of the decree-law of the 30th of January 1947), where measurements were made considering several types of decouplers, such as: discrete bearings with multiple thickness and/or different void depth (filled in totally or partially with insulation material) and mats and strips placed between the CLT slab and different timber, cement and gypsum-based boards with and without use of the well-known constrained layer damping technique. This paper will present the findings of the test campaign.

Outdoor Concert Hotel Acoustics

VAI Resort, situated across the street from the site of Super Bowl LVII, presents a number of acoustical challenges, not the least of which is a world-class, 360-degree outdoor performance venue. Performers will blast an 8-storey hotel located 250 ft away with music of all types, which audiences will enjoy from the balconies of their hotel rooms. The challenge of modeling such a venue comes in simplifying it down to manageable pieces. Does a balcony with a hotel room behind it behave like a Helmholtz resonator? How do the acoustics change if 90% of the balconies are open to the hotel rooms beyond? What if 50% are open? 25% are open? Such a variable acoustic space presents a significant modeling challenge. A methodology for tackling such a large-scale project is presented, with modeling results, auralizations, and comparisons to real-world measurements. Findings include a swing in RT60 of more than 25% when all balcony doors are opened versus closed.

The effects of speech masking on neural tracking of acoustic and semantic features of natural speech

Listening environments contain background sounds that mask speech and lead to communication challenges. Sensitivity to slow acoustic fluctuations in speech can help segregate speech from background noise. Semantic context can also facilitate speech perception in noise, for example, by enabling prediction of upcoming words. However, not much is known about how different degrees of background masking affect the neural processing of acoustic and semantic features during naturalistic speech listening. In the current electroencephalography (EEG) study, participants listened to engaging, spoken stories masked at different levels of multi-talker babble to investigate how neural activity in response to acoustic and semantic features changes with acoustic challenges, and how such effects relate to speech intelligibility. The pattern of neural response amplitudes associated with both acoustic and semantic speech features across masking levels was U-shaped, such that amplitudes were largest for moderate masking levels. This U-shape may be due to increased attentional focus when speech comprehension is challenging, but manageable. The latency of the neural responses increased linearly with increasing background masking, and neural latency change associated with acoustic processing most closely mirrored the changes in speech intelligibility. Finally, tracking responses related to semantic dissimilarity remained robust until severe speech masking (−3 dB SNR). The current study reveals that neural responses to acoustic features are highly sensitive to background masking and decreasing speech intelligibility, whereas neural responses to semantic features are relatively robust, suggesting that individuals track the meaning of the story well even in moderate background sound.

Comparing tools for automation of formant estimation in diverse pediatric populations

Pediatric vowel productions are notoriously hard to reliably quantify. Listener judgments and transcription are subjective, show low intra- and interrater reliability, and are influenced by listener bias. Formant estimation may offer more objectivity, but child speech is fraught with acoustic challenges. Children have less refined articulatory control and they make more production errors. They have high fundamental frequencies, wide formant bandwidths, more variable formant values, and increased subglottal coupling relative to adult speech. Historically, estimation of pediatric formants has been done manually, which is laborious and time-consuming. In recent years, automation tools have been developed to speed up the process. However, these tools have not been widely tested on pediatric speech samples. Even more critically, these tools have not been tested on diverse children. This study uses speech samples from children of color, children with disabilities, and children with both of these identities to compare three automation tools: SpeechMark® (Boyce etal., 2012), Fast Track™ (Barreda, 2021), and a custom Praat® (Boersma &amp; Weenink, 2021) script written by the first author. Outcomes of each tool will be compared and contrasted. The discussion will review the considerations, benefits, and tradeoffs of each automation tool when working with diverse pediatric speech samples.

Challenging rules of thumb to redefine flexibility

The recently completed Lindemann Performing Arts Center on the Brown University campus is an exploration in all things flexible. To satisfy the programmatic needs of Brown Arts Initiative, the primary user of this new building, who needed five rooms but only got one, the Main Hall redefined the concept of multiuse hall. All sixsurfaces that define the major acoustically supportive surfaces (ceiling elements, walls, and floors) move to manipulate the otherwise beautifully simple architectural concept into five room configurations—Orchestra, Recital, End Stage Theatre, Experimental Media, and large Flat Floor. A mix of manual and motorized curtains and banners adds still more flexibility. As the paint still dries on the building, this paper will investigate the acoustic challenges, happy accidents, and areas where we might have done with less (or more) in a building that is sometimes heavy handed and sometimes a light touch. The paper will cover topics such as glass as a major reflecting surface, wall buildups that break rules of thumb to produce warm acoustic responses, use of variable acoustic solutions, and ensemble to audience size ratios that challenge conventional wisdom.

Andantes con Cervantes

Andantes con Cervantes

Constrained layer damping concept used on isolated gym floors. Better than Concrete?

As the global fitness trends continues in a post-pandemic world, intra-building disruptions from high-energy fitness create serious acoustical challenges. Solutions from simple roll-out mats and rubber tiles to concrete floating floors supported by spring jack-up isolators are used to achieve acoustical separation for gyms. Understanding the sources of sound and vibration produced in fitness environments and finding effective solutions was a journey that CDM Stravitec began in the 1970s and this area of the acoustics industry has been intensively researched as part of the development of our range of lightweight floating floors. As part of this research, we extensively investigated how the concept of constrained layer damping (CLD) could be employed to mitigate vibration radiation through structures. In the application of fitness flooring, the CLD functions to restrict the physical movement between the rigid board layers decreases the area of influence from the impact, reduces the energy radiation through the composite panel system to its support and subsequently reduces the energy transfer into the structure. Our research has also shown that elastomeric supports balance low-resonant frequency performance to prevent energy build-up at the driving frequencies and can achieve high levels of transmission loss which are comparable to concrete based solutions.

Improved acoustics for semi-enclosed spaces in the proximity of residential buildings

Continuous urban densification exacerbates acoustic challenges for residents of housing complexes. They are confronted with higher noise immission from railway, road traffic, construction, as well as louder neighborhood acoustic environments. Thereby, not only noise immission indoors is associated with stress, annoyance, and sleep disturbance, but also the immediate outdoor living environment (e.g., courtyards, private gardens, and playgrounds, etc.) can be acoustically unpleasant and annoying. This non-exhaustive narrative review paper elaborates on the role of a number of design parameters on improving the quality of the outdoor soundscape of housing complexes: architectural and morphological design, facade material characteristics, balconies, greenery, ground, background sounds, and several factors concerning quality of sounds (e.g., multisensory perception, holistic design, the relevance of space, context, social factors, co-creation, etc.). It mainly covers literature including both acoustical (e.g., sound pressure level and room acoustical parameters) and human/perceptual (e.g., comfort and annoyance) factors. A series of recommendations are presented here as to how the semi-enclosed outdoor spaces in the proximity of residential complexes can be acoustically improved.

Innovative Solutions for Acoustic Challenges in Tall Slender Skyscrapers

Innovative Solutions for Acoustic Challenges in Tall Slender Skyscrapers